Reflexões sobre a utilização do Teste de Progresso na avaliação programática do estudante

Resumo: Introdução: O Teste de Progresso (TP) constitui modalidade estabelecida e bem-sucedida de avaliação de conhecimentos do estudante das profissões da saúde, principalmente os de Medicina, com potencial de contribuir substancialmente para as finalidades formativa e informativa (controle de qualidade e indicação de melhoria nos processos de ensino e aprendizagem). Adicionalmente, o TP apresenta características adequadas à sua inclusão em sistemas institucionais de avaliação que privilegiem a finalidade formativa, como a avaliação programática (AP), mas que cumprem também a somativa. Nas escolas que vêm definindo ações visando à introdução da AP em seus cursos de graduação, é necessária a reflexão sobre as fortalezas e limitações da utilização do TP no sistema de avaliação. Desenvolvimento: A partir das considerações de um grupo de trabalho representativo de toda a instituição, incumbido de propor meios de introdução da AP em um novo currículo para o curso de Medicina, contando com assessoria internacional com experiência tanto no TP como na AP, elaborou-se reflexão sobre esse tema, baseada na experiência dos autores e em dados da literatura. Propõe-se que, dentro da perspectiva longitudinal da AP, o TP constitua um dos pilares na avaliação de conhecimentos. O TP pode servir de base para acompanhamento do estudante, no contexto da sua turma (coorte), e seus resultados devem ser discutidos com o mentor que o acompanha e lhe dá suporte. O TP deve ter também papel central na gestão, como fonte de informações para eventual revisão e qualificação do currículo e das suas atividades de ensino e aprendizagem. É previsível que a utilização do TP na AP traga diferentes desafios e barreiras, que serão mais facilmente superados se houver na instituição experiências já consolidadas de aplicação de exames institucionais e de desenvolvimento docente para a elaboração de questões objetivas de boa qualidade. Conclusão: A efetividade do TP dentro do sistema institucional de AP vai depender de medidas que visem aumentar a sua efetividade na avaliação e que estimulem a participação ativa do estudante, refletindo sobre seu desempenho no TP, com o apoio do seu mentor, de modo a se engajar em ações que fomentem a autorregulação da aprendizagem

Glucocorticoid-Mediated Regulation of Circadian Rhythms: Interface with Energy Homeostasis and Reproduction

All living organisms have evolved by developing concomitant physiological and behavioral adaptations to environment. Through these processes, biological rhythms, such as reproduction, can be synchronized by environmental cues, which include not only the light/dark cycle itself but also the feeding pattern. These adaptations depend on two highly conserved and interrelated systems: an endogenous timing system and the hypothalamic-pituitary-adrenal (HPA) axis. In mammals, the biological circadian rhythms are controlled by a “master oscillator,” the suprachiasmatic nucleus of the hypothalamus (SCN). Through neural signals to paraventricular nucleus of hypothalamus (PVN), the SCN also modulates the activation of the HPA axis, ultimately resulting in the circadian rhythm of glucocorticoid secretion by the adrenal cortex. Glucocorticoids, in turn, are well known for their important role in the regulation of energy homeostasis. Accordingly, obese animals exhibit increased glucocorticoid levels and are more susceptible to glucocorticoid-induced anabolic effects. In parallel, glucocorticoids modulate reproductive function and fertility: at physiological levels, glucocorticoids control the timing of puberty onset and gonadal steroidogenesis, as well modulate the immune system, which determines conception and pregnancy progression. However, stress-induced glucocorticoid secretion may exert a dual effect on reproductive function

Arcuate AgRP, but not POMC neurons, modulate paraventricular CRF synthesis and release in response to fasting

Background: The activation of the hypothalamic–pituitary–adrenal (HPA) axis is essential for metabolic adaptation in response to fasting. However, the neurocircuitry connecting changes in the peripheral energy stores to the activity of hypothalamic paraventricular corticotrophin-releasing factor (CRFPVN) neurons, the master controller of the HPA axis activity, is not completely understood. Our main goal was to determine if hypothalamic arcuate nucleus (ARC) POMC and AgRP neurons can communicate fasting-induced changes in peripheral energy stores, associated to a fall in plasma leptin levels, to CRFPVN neurons to modulate the HPA axis activity in mice. Results: We observed increased plasma corticosterone levels associate with increased CRFPVN mRNA expression and increased CRFPVN neuronal activity in 36 h fasted mice. These responses were associated with a fall in plasma leptin levels and changes in the mRNA expression of Agrp and Pomc in the ARC. Fasting-induced decrease in plasma leptin partially modulated these responses through a change in the activity of ARC neurons. The chemogenetic activation of POMCARC by DREADDs did not affect fasting-induced activation of the HPA axis. DREADDs inhibition of AgRPARC neurons reduced the content of CRFPVN and increased its accumulation in the median eminence but had no effect on corticosterone secretion induced by fasting. Conclusion: Our data indicate that AgRPARC neurons are part of the neurocircuitry involved in the coupling of PVNCRF activity to changes in peripheral energy stores induced by prolonged fasting.Fil: Alves Fernandes, Alan Carlos. University Of Ribeirao Preto; BrasilFil: Pereira de Oliveira, Franciane. Universidade Federal de Sao Paulo.; BrasilFil: Fernandez, Gimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: da Guia Vieira, Luane. University Of Ribeirao Preto; BrasilFil: Gugelmin Rosa, Cristiane. University Of Ribeirao Preto; BrasilFil: do Nascimento, Taís. University Of Ribeirao Preto; BrasilFil: de Castro França, Suzelei. University Of Ribeirao Preto; BrasilFil: Donato Jr, Jose. Universidade de Sao Paulo. Departamento de Fisiología; BrasilFil: Vella, Kristen R.. Weill Cornell Medical College; Estados UnidosFil: Antunes Rodrigues, Jose. University Of Ribeirao Preto; BrasilFil: Mecawi , André. Universidade Federal de Sao Paulo.; BrasilFil: Perello, Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Leico Kagohara Elias, Lucila. University Of Ribeirao Preto; BrasilFil: Rorato, Rodrigo. Universidade Federal de Sao Paulo.; Brasi

Cholecystokinin and hypothalamic corticotrophin-releasing factor participate in endotoxin-induced hypophagia

Cholecystokinin (CCK) provides a meal-related signal that activates brainstem neurons, which have reciprocal interconnections with the hypothalamic paraventricular nucleus. Neurons that express corticotrophin-releasing factor (CRF) in the hypothalamus possess anorexigenic effects and are activated during endotoxaemia. This study investigated the effects of CCK(1) receptor blockade on lipopolysaccharide (LPS)-induced hypophagia and hypothalamic CRF neuronal activation. Male Wistar rats were pretreated with a specific CCK(1) receptor antagonist (devazepide; 1 mg kg(-1); I.P.) or vehicle; 30 min later they received LPS (100 mu g kg(-1); I.P.) or saline injection. Food intake, corticosterone responses and Fos-CRF and Fos-alpha-melanocyte-stimulating hormone (alpha-MSH) immunoreactivity in the hypothalamus and Fos-tyrosine hydroxylase immunoreactivity in the nucleus of the solitary tract (NTS) were evaluated. In comparison with saline treatment, LPS administration decreased food intake and increased plasma corticosterone levels, as well as the number of Fos-CRF and Fos-tyrosine hydroxylase double-labelled neurons in vehicle-pretreated rats; no change in Fos-alpha-MSH immunoreactivity was observed after LPS injection. In saline-treated animals, devazepide pretreatment increased food intake, but it did not modify other parameters compared with vehicle-pretreated rats. Devazepide pretreatment partly reversed LPS-induced hypophagia and Fos-CRF and brainstem neuronal activation. Devazepide did not modify the corticosterone and Fos-alpha-MSH responses in rats treated with LPS. In conclusion, the present data suggest that LPS-induced hypophagia is mediated at least in part by CCK effects, via CCK(1) receptor, on NTS and hypothalamic CRF neurons.FAPESPCNP

LPS-Induced Low-Grade Inflammation Increases Hypothalamic JNK Expression and Causes Central Insulin Resistance Irrespective of Body Weight Changes

Metabolic endotoxemia contributes to low-grade inflammation in obesity, which causes insulin resistance due to the activation of intracellular proinflammatory pathways, such as the c-Jun N-terminal Kinase (JNK) cascade in the hypothalamus and other tissues. However, it remains unclear whether the proinflammatory process precedes insulin resistance or it appears because of the development of obesity. Hypothalamic low-grade inflammation was induced by prolonged lipopolysaccharide (LPS) exposure to investigate if central insulin resistance is induced by an inflammatory stimulus regardless of obesity. Male Wistar rats were treated with single (1 LPS) or repeated injections (6 LPS) of LPS (100 μg/kg, IP) to evaluate the phosphorylation of the insulin receptor substrate-1 (IRS1), Protein kinase B (AKT), and JNK in the hypothalamus. Single LPS increased the expression of pIRS1, pAKT, and pJNK, whereas the repeated LPS treatment failed to recruit pIRS1 and pAKT. The 6 LPS treated rats showed increased total JNK and pJNK. The 6 LPS rats became unresponsive to the hypophagic effect induced by central insulin administration (12 μM/5 μL, ICV). Prolonged exposure to LPS (24 h) impaired the insulin-induced AKT phosphorylation and the translocation of the transcription factor forkhead box protein O1 (FoxO1) from the nucleus to the cytoplasm of the cultured hypothalamic GT1-7 cells. Central administration of the JNK inhibitor (20 μM/5 μL, ICV) restored the ability of insulin to phosphorylate IRS1 and AKT in 6 LPS rats. The present data suggest that an increased JNK activity in the hypothalamus underlies the development of insulin resistance during prolonged exposure to endotoxins. Our study reveals that weight gain is not mandatory for the development of hypothalamic insulin resistance and the blockade of proinflammatory pathways could be useful for restoring the insulin signaling during prolonged low-grade inflammation as seen in obesity

Cannabinoid CB1 receptor restrains accentuated activity of hypothalamic corticotropin-releasing factor and brainstem tyrosine hydroxylase neurons in endotoxemia-induced hypophagia in rats

It is well known that endocannabinoids play an important role in the regulation of food intake and body weight. Endocannabinoids and cannabinoid receptors are found in the hypothalamus and brainstem, which are central areas involved in the control of food intake and energy expenditure. Activation of these areas is related to hypophagia observed during inflammatory stimulus. This study investigated the effects of cannabinoid (CB1) receptor blockade on lipopolysaccharide (LPS)-induced hypophagia. Male Wistar rats were pretreated with rimonabant (10 mg/kg, by gavage) or vehicle; 30 min later they received an injection of either LPS (100 mu g/kg, intraperitoneal) or saline. Food intake, body weight, corticosterone response, CRF and CART mRNA expression, Fos-CRF and Fos-alpha-MSH immunoreactivity in the hypothalamus and Fos-tyrosine hydroxylase (TH) immunoreactivity in the brainstem were evaluated. LPS administration decreased food intake and body weight gain and increased plasma corticosterone levels and CRF mRNA expression in the PVN. We also observed an increase in Fos-CRF and Fos-TH double-labeled neurons after LPS injection in vehicle-pretreated rats, with no changes in CART mRNA or Fos-alpha-MSH immunoreactive neurons in the ARC. In saline-treated animals, rimonabant pretreatment decreased food intake and body weight gain but did not modify hormone response or Fos expression in the hypothalamus and brainstem compared with vehicle-pretreated rats. Rimonabant pretreatment potentiated LPS-induced hypophagia, body weight loss and Fos-CRF and Fos-TH expressing neurons. Rimonabant did not modify corticosterone, CRF mRNA or Fos-alpha-MSH responses in rats treated with LPS. These data suggest that the endocannabinoid system, mediated by CB1 receptors, modulates hypothalamic and brainstem circuitry underlying the hypophagic effect during endotoxemia to prevent an exaggerated food intake decrease. This article is part of a Special Issue entitled 'Central Control of Food Intake'. (C) 2011 Elsevier Ltd. All rights reserved.FAPESPFAPESPFAEPAFAEPACNPqCNP

Carbon monoxide and nitric oxide modulate hyperosmolality-induced oxytocin secretion by the hypothalamus in vitro

OT (oxytocin) is secreted from the posterior pituitary gland, and its secretion has been shown to be modulated by NO (nitric oxide). In rats, OT secretion is also stimulated by hyperosmolarity of the extracellular fluid. Furthermore, NOS (nitric oxide synthase) is located in hypothalamic areas involved in fluid balance control. In the present study, we evaluated the role of the NOS/NO and HO (haem oxygenase)/CO (carbon monoxide) systems in the osmotic regulation of OT release from rat hypothalamus in vitro. We conducted experiments on hypothalamic fragments to determine the following: (i) whether NO donors and NOS inhibitors modulate OT release and (ii) whether the changes in OT response occur concurrently with changes in NOS or HO activity in the hypothalamus. Hyperosmotic stimulation induced a significant increase in OT release that was associated with a reduction in nitrite production. Osmotic stimulation of OT release was inhibited by NO donors. NOS inhibitors did not affect either basal or osmotically stimulated OT release. Blockade of HO inhibited both basal and osmotically stimulated OT release, and induced a marked increase in NOS activity. These results indicate the involvement of CO in the regulation of NOS activity. The present data demonstrate that hypothalamic OT release induced by osmotic stimuli is modulated, at least in part, by interactions between NO and CO